Yes and longer than that, always I dare say. I suspect one of the triggers lies in a certain combination of traits that effect the immune system. Not that the immune system is weak mind you. Just the immune system effects the pheromones that are excreted which creates our BO (in part). It is this smell that attracts or repels people of the opposite sex. Someone who enjoys the smell of your BO (as is common with lovers), means that the immune systems complement each other (ones immune system is strong where the other ones is weak and vice versa). Of course this is just theory, I'm not stating any of this as fact. I very well could be wrong.
I've seen a study where people find the BO of the people they're sexually attracted to more appealing, eg gay men find other gay men's BO more appealing than anyone else's, straight women find straight men's BO more appealing, etc. I don't know what any of that has to do with gays being a sign of impending extinction though?